In both service water systems and heating water systems, temperature variations may cause the liquid medium--usually water--to undergo volume fluctuations. Such temperature dependent volume fluctuations are compensated for by expansion tanks of the type known by DE 4013897 C2, for example. These expansion tanks are placed under a predetermined pressure to urge incoming water back into the respective systems as temperatures change.
Conventional service water systems are pressurized to approximately 4 bar, whereas heating systems conventionally operate at a pressure of 1.5 to 3 bar. The expansion tanks are necessary for technical reasons, but occupy a certain amount of space and cause additional material expenditures.